Skip to main content
. 2009 Jul 8;97(1):388–396. doi: 10.1016/j.bpj.2009.04.022

Figure 2.

Figure 2

Gramicidin channels. (A) Solution exchange protocol and transient currents during rapid solution exchange on a SSM with adsorbed liposomes containing gramicidin. The narrow peak currents close to 0.5 and 1 s are valve switching artifacts. Note that the gray boxes indicate timing of the valve driving voltage. Actual valve switching and solution exchange are delayed by up to 50 ms. At t = 0.5 s a K+ containing solution is applied to the SSM. After a short delay time a transient current (arrow) indicating translocation of positive charge into the liposome is observed. In addition to a basic buffer of 50 mM Hepes(Tris) pH 7.0 the different solutions contained: 10 mM NMGCl (NMG) or 10 mM KCl (K). (B) Expanded view of the transient currents obtained with different cations. For comparison the small negative artifacts obtained in the absence of gramicidin in the liposomes are shown (dashed lines in the order of increasing amplitude Li, Na, K). Solution composition as described above except for the permeant cation that was 10 mM KCl (trace K+), 10 mM NaCl (trace Na+), and 10 mM LiCl (trace Li+).